W43A explained

W43A or IRAS 18450-0148 is a late-type star with an envelope of OH/IR type with a magnetically collimated jet (a protoplanetary nebula). The star is in the early stages of becoming a planetary nebula, a process that will take several thousand years.

Further reading

• 2002Natur.417..829I. 4. Imai, Hiroshi. Obara, Kumiko. Diamond, Philip J.. Omodaka, Toshihiro. Sasao, Tetsuo . A collimated jet of molecular gas from a star on the asymptotic giant branch. Nature . 417. 829–831. 2002. 10.1038/nature00788. 12075345. 6891. 27760425.
• 2005ApJ...622L.125I. 4. Imai, Hiroshi. Nakashima, Jun-ichi. Diamond, Philip J.. Miyazaki, Atsushi. Deguchi, Shuji. A Biconically Expanding Flow in W43A Traced by SiO Maser Emission. The Astrophysical Journal . 622. 2. L125–L128. 2005. 10.1086/429820. free.
• 2007ApJ...658.1096D. Deacon, R. M.. Chapman, J. M.. Green, A. J.. Sevenster, M. N.. H2O Maser Observations of Candidate Post-AGB Stars and Discovery of Three High-Velocity Water Sources. The Astrophysical Journal . 658. 2. 1096–1113. 2007. 10.1086/511383. astro-ph/0702086 . 7776074.
• Polarimetric observations of OH masers in proto-planetary nebulae. M. Szymczak. E. Gérard. amp . Astronomy & Astrophysics . 423. 209–219. 2004. 10.1051/0004-6361:20040461. 2004A&A...423..209S. astro-ph/0405316 . 15651391.